The picture shows the back (i.e. rail) of a chair and the mechanism by which it was fastened to the stile. I'm not sure how those spiky pieces were initially inserted. Perhaps they "opened up" like a toggle bolt. In any case, I don't think that hammering them back in would make for a reliable connection. Given where I'm at, what course of action would you recommend for fixing the chair? My current plan is to used a dowel and then hope to find screw of the right depth and head.

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  • cool photo! I look forward to learning more about those little metal Jughead hats. Maybe you could include a picture of what you plan to reattach this to?
    – Willk
    Commented Jul 14, 2021 at 0:57
  • It looks like wood dowels were used for connections. Can you provide the part it connected to? If it was the leg, I doubt you can change the fastening method but strengthen the connections.
    – r13
    Commented Jul 14, 2021 at 1:13
  • Can you confirm that this is solid wood, not particle board/pressed wood or other manufactured wood product? Also, a larger picture of what attaches to this and the angle at which it attaches would be most helpful. Indicating what tools you have would help, as well. Odds are good that your "replace it with a dowel and screws" idea would work well.
    – FreeMan
    Commented Jul 14, 2021 at 11:22

3 Answers 3


Those do look like expansion anchors, AKA expansion bolts, as you state. However, because of the very shallow depth of the holes (which led to a lack of strength and early failure), it might be difficult to find a replacement that would hold.

If appearance is not important, I'd drill through the hole and use two nuts, with washers, to hold each screw. Longer screws might be needed, in that case, so there might be no need to match the threads of the existing screws.

If appearance is important, you could try forcing the cone nut out of the shell, and then squeezing the prongs of the shell closed with pliers or vise. Repair the damaged wood and reinforce, perhaps with epoxy or a metal plate on the hidden side, re-drill the holes, and reuse the old expansion bolt. How well it will hold depends on use and strength of repaired wood, and this would not be as strong as a through-bolt.


drill the holes larger and use threaded inserts.

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In the inserts are too long grind them shorter after installing them.

It looks like plywood. these will hold very well in plywood.


T-nuts, or tee-nuts will work fine, if the look on the other side isn't too important. They bite into the opposite side of the wood, and the bolts can be cut off flush when tight. Drill out the hole appropriately, and fill with epoxy resin as required.

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